scholarly journals Current knowledge of gene flow in plants: implications for transgene flow

2003 ◽  
Vol 358 (1434) ◽  
pp. 1163-1170 ◽  
Author(s):  
Norman C. Ellstrand
Keyword(s):  
Gene Flow ◽  
Rare Species ◽  
Current Knowledge ◽  
Extinction Risk ◽  
Transgenic Crops ◽  
Wild Relatives ◽  
Wild Populations ◽  
Transgene Flow ◽  
Negative Impacts

Plant evolutionary biologists' view of gene flow and hybridization has undergone a revolution. Twenty–five years ago, both were considered rare and largely inconsequential. Now gene flow and hybridization are known to be idiosyncratic, varying with the specific populations involved. Gene flow typically occurs at evolutionarily significant rates and at significant distances. Spontaneous hybridization occasionally has important applied consequences, such as stimulating the evolution of more aggressive invasives and increasing the extinction risk for rare species. The same problems have occurred for spontaneous hybridization between crops and their wild relatives. These new data have implications for transgenic crops: (i) for most crops, gene flow can act to introduce engineered genes into wild populations; (ii) depending on the specific engineered gene(s) and populations involved, gene flow may have the same negative impacts as those observed for traditionally improved crops; (iii) gene flow's idiosyncratic nature may frustrate management and monitoring attempts; and (iv) intercrop transgene flow, although rarely discussed, is equally worthy of study.

scholarly journals Voter Model and Biased Voter Model in Heterogeneous Environments

2007 ◽  
Vol 44 (03) ◽  
pp. 770-787
Author(s):  
N. Lanchier ◽  
C. Neuhauser
Keyword(s):  
Gene Flow ◽  
Pollen Dispersal ◽  
Transgenic Crops ◽  
Wild Relatives ◽  
Voter Model ◽  
Wild Plants ◽  
Transgenic Crop ◽  
Heterogeneous Environments ◽  
Wild Type ◽  
Type Gene

With the rapid adoption of transgenic crops, gene flow from transgenic crops to wild relatives through pollen dispersal is of significant concern and warrants both empirical and theoretical studies to assess the risk of introduction of transgenes into wild populations. We propose to use the (biased) voter model in a heterogeneous environment to investigate the effects of recurrent gene flow from transgenic crop to wild relatives. The model is defined on the d-dimensional integer lattice that is divided into two parts, Δ and Z d \ Δ. Individuals carrying the transgene and individuals carrying the wild type gene compete according to the evolution rules of a (biased) voter model on Z d \ Δ, while the process is conditioned to have only individuals carrying the transgene on Δ. Our main findings suggest that unless transgenes confer increased fitness in wild relatives, introgression of transgenes into populations of wild plants is slow and may even be reversible without intervention. Our study also addresses the effects of different spatial planting patterns of transgenic crops on the rate of introgression.

scholarly journals Voter Model and Biased Voter Model in Heterogeneous Environments

2007 ◽  
Vol 44 (3) ◽  
pp. 770-787 ◽  
Author(s):  
N. Lanchier ◽  
C. Neuhauser
Keyword(s):  
Gene Flow ◽  
Pollen Dispersal ◽  
Transgenic Crops ◽  
Wild Relatives ◽  
Voter Model ◽  
Wild Plants ◽  
Transgenic Crop ◽  
Heterogeneous Environments ◽  
Wild Type ◽  
Type Gene

With the rapid adoption of transgenic crops, gene flow from transgenic crops to wild relatives through pollen dispersal is of significant concern and warrants both empirical and theoretical studies to assess the risk of introduction of transgenes into wild populations. We propose to use the (biased) voter model in a heterogeneous environment to investigate the effects of recurrent gene flow from transgenic crop to wild relatives. The model is defined on the d-dimensional integer lattice that is divided into two parts, Δ and Zd \ Δ. Individuals carrying the transgene and individuals carrying the wild type gene compete according to the evolution rules of a (biased) voter model on Zd \ Δ, while the process is conditioned to have only individuals carrying the transgene on Δ. Our main findings suggest that unless transgenes confer increased fitness in wild relatives, introgression of transgenes into populations of wild plants is slow and may even be reversible without intervention. Our study also addresses the effects of different spatial planting patterns of transgenic crops on the rate of introgression.

Indirect estimates reveal the potential of transgene flow in the crop–wild–weed Sorghum bicolor complex in its centre of origin, Ethiopia

2016 ◽  
Vol 15 (6) ◽  
pp. 496-505
Author(s):  
Asfaw Adugna ◽  
Endashaw Bekele
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Phenotypic Traits ◽  
Wild Populations ◽  
Centre Of Origin ◽  
Transgene Flow ◽  
Potential Risks ◽  
Cultivated Populations ◽  
Simple Sequence

AbstractA study was carried out between 2008 and 2011 to investigate the potential risks of gene flow and its consequences in the crop–wild–weed S. bicolor complex in Ethiopia to aid efforts to conserve genetic diversity. Morphological measurements and genomic DNA samples were taken in situ from 30 wild and eight cultivated populations representing a total of 760 samples from five regions. Genetic diversity, gene flow, population structure and outcrossing rates of wild populations were computed using phenotypic measurements and/or polymorphic simple sequence repeat (SSR) markers. Moreover, morphological analyses of fitness of crop–wild hybrids were studied. High diversity was observed among the wild/weedy sorghum populations for phenotypic traits and SSRs. SSR diversity was high in both wild and cultivated populations, but the magnitude was greater in the former. Gene flow between the wild and the cultivated sorghum was observed to be higher than that within either pool. Wild sorghums exhibited variation in the multilocus outcrossing rate (range = 0.31–0.65) and fitness was not compromised in most wild × crop hybrids. The study indicated that crop-to-wild gene flow is possible in Ethiopia. Thus, genes from transgenic sorghum are expected to enter into the wild and non-transgenic cultivated populations and may spread and persist, if transgenic sorghum is deployed in Ethiopia and in other countries of Africa, which may pose risk of introduction of unwanted effects, which in turn may lead to loss of genetic diversity.

scholarly journals Gene flow from transgenic soybean, developed to obtain recombinant proteins for use in the skin care industry, to non-transgenic soybean

2020 ◽  
Vol 63 (1) ◽  
Author(s):  
Do Young Kim ◽  
Min Sik Eom ◽  
Hye Jin Kim ◽  
Eun Mi Ko ◽  
In-Soon Pack ◽  
...  
Keyword(s):  
Gene Flow ◽  
Growth Factor ◽  
Recombinant Proteins ◽  
Soybean Seed ◽  
Transgenic Crops ◽  
Skin Care ◽  
Transgenic Soybean ◽  
M Gene ◽  
Care Industry ◽  
Transgene Flow

Abstract Soybean has been recognized as a useful platform for heterologous protein production. This study compared the pollen characteristics of transgenic and non-transgenic soybean and investigated the rate of gene flow from transgenic soybean events, developed to obtain recombinant proteins (such as human epidermal growth factor, insulin-like growth factor 1, or thioredoxin) for use in the skin care industry, to non-transgenic soybean under field conditions, and determined the distance at which gene flow could occur. The lack of significant differences in pollen grain size, viability and pollen germination rates between transgenic and non-transgenic cultivars indicates that the overexpression of transgenes did not alter pollen characteristics in soybean. The highest rates of gene flow from the three transgenic soybean events to non-transgenic soybean ranged from 0.22 to 0.46% at the closest distance (0.5 m). Gene flow was observed up to 13.1 m from the transgenic plots. Our data fell within the ranges reported in the literature and indicate that an isolation distance greater than at least 13 m from transgenic soybean is required to prevent within-crop gene flow in soybean. As the potential markets for transgenic crops as a recombinant protein factory increase, gene flow from transgenic to non-transgenic conventional crops will become a key decision factor for policy makers during the approval process of transgenic crops. Our study may provide useful baseline data for the prevention of transgenic soybean seed contamination caused by transgene flow.

Controlling transgene flow from engineered crops to unintended hosts by molecular approaches.

2021 ◽  
pp. 118-124
Author(s):  
C. Neal Stewart Jr
Keyword(s):  
Gene Flow ◽  
Male Sterility ◽  
Growth And Development ◽  
Management Strategies ◽  
Transgenic Crops ◽  
Molecular Approaches ◽  
Transgene Flow ◽  
Plant Sexual Reproduction ◽  
Crop Biotechnology ◽  
Hybridization And Introgression

Abstract For most transgenic crops, the purported ecological risk from transgenic-host hybridization and introgression to unintended host species is negligible. Nonetheless, there remains a risk-associated focus on the potential for gene flow in the governance and regulation of crop biotechnology. Because of uncertainties in the large world of biology as well as regulatory certainties (regulations will likely not diminish), researchers and stakeholders have a great interest in eliminating or substantially decreasing gene flow from transgenic crops. To that end, numerous approaches have been investigated for limiting transgene flow via hybridization and introgression to unintended hosts. While such bioconfinement may be accomplished by ecological and management strategies as discussed elsewhere in this book, this chapter focuses on mitigating unintended gene flow from engineered crops by way of genetic engineering itself. The chapter will mainly discuss the manipulation of relatively simple means to alter plant sexual reproduction and plant growth and development to control transgene flow, with the desired outcome being the prevention of transgenes from moving and/or introgression into free-living unintended hosts. These approaches include: (i) decreasing or delaying flowering; (ii) eliminating pollen production via male sterility or selective male sterility; (iii) removing transgenes from pollen or eggs by gene use restriction technologies; and (iv) kill switches. Emerging synthetic biology approaches that may be used for transgene bioconfinement are explored. Taken together, the same molecular biology strategies that are used to improve crops can also help assure their biosafety.

Recent long-distance transgene flow into wild populations conforms to historical patterns of gene flow in cotton (Gossypium hirsutum) at its centre of origin

2011 ◽  
Vol 20 (19) ◽  
pp. 4182-4194 ◽  
Author(s):  
A. WEGIER ◽  
A. PIÑEYRO-NELSON ◽  
J. ALARCÓN ◽  
A. GÁLVEZ-MARISCAL ◽  
E. R. ÁLVAREZ-BUYLLA ◽  
...  
Keyword(s):  
Gene Flow ◽  
Gossypium Hirsutum ◽  
Wild Populations ◽  
Long Distance ◽  
Centre Of Origin ◽  
Transgene Flow

Population fragmentation causes inadequate gene flow and increases extinction risk

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Gene Flow ◽  
Extinction Risk ◽  
Random Mating ◽  
Large Population ◽  
Isolated Population ◽  
Population Fragmentation ◽  
Single Population ◽  
Total Size ◽  
Limited Gene Flow

Most species now have fragmented distributions, often with adverse genetic consequences. The genetic impacts of population fragmentation depend critically upon gene flow among fragments and their effective sizes. Fragmentation with cessation of gene flow is highly harmful in the long term, leading to greater inbreeding, increased loss of genetic diversity, decreased likelihood of evolutionary adaptation and elevated extinction risk, when compared to a single population of the same total size. The consequences of fragmentation with limited gene flow typically lie between those for a large population with random mating and isolated population fragments with no gene flow.

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